Ok so after years of loving this series, I just got into this. I understand most of it but I have a few questions:

1. I know there is a limit to how many EV's you can get in total. 510 per pokemon/ 255 per stat. Does this reset with you level making it able to get 255 EV's per level? I really doubt it but just making sure.

2. If the EVs do not reset each level, does killing 255 of the pokemon with the EV you desire (Assuming you have no EV items or the Poke virus) completely max out that stat as far as gaining EVs?

Any other information you think I might need regarding EV training is greatly appreciated.

Yes, killing 255 of a pokemon with an EV for the stat you're going for would max it. However, not all Pokemon just give one EV, some give two or one for one stat and one for another. And a few give three.

Here's how EVs work. EVs are a hidden value that act as bonuses for your stats. Each Pokemon gives you EVs when you beat it. For example, a Bidoof gives you one health EV. For every four EVs, your Pokemon's stat increases by one in that category. However, the stat bonuses are distributed on the way to level 100. You don't get them immediately, and you don't get all the ones you earned each level once you level. It's evenly distributed. So if you got a level 99 and EV trained it, it'd get all the stats when it levels. If you had a level one and somehow got it 100 stats worth of EVs, you'd get around 1 more than you normally would for that stat with each level you gain until you reached 100. Note, because of this, it is impossible to EV train a level 100. And as you said, you can only get 255 in each stat, and 510 in total. This is the reason for EV training.
EV training requires a lot of counting. I'd get a sheet of paper to keep track of stuff on. You need to know exactly how many EVs you have, how many you want, and how many each Pokemon gives you.
If you've ever fought with your Pokemon, it has EVs. You probably won't be able to remember all the battles they had, and even if you did, they probably don't have all the EVs you want. For this reason, you want to either EV train a wild Pokemon you just caught, or EV train one you hatched from an egg. Alternatively, there are berries that take away EVs. They're the ones that say "makes the Pokemon more friendly, but decreases its base [hp, atk, def, etc] stat". What this actually does is lower the EVs. One berry will lower that Pokemon's EVs by 10 in that stat, or if there are over 100 EVs in that stat, it will lower it to 100. In this sense, I believe it takes 11 berries to be completely sure the Pokemon has 0 EVs in that stat. Best start planting.
Now, you need to know how much each Pokemon gives you. I'd look up a site that shows the best places to EV train for a stat, and what Pokemon give you it. For example, I EV'd for special attack in the old Chateau in Diamond, fighting Ghastlys, haunters, and Gengars, for one, two, and three spc atk EVs, respectively. Run from ones that will not give you the EVs you need. Be sure to record how many EVs you get from each Pokemon. Also, one thing that helps are Vitamins. They're like the berries in reverse. The vitamins HP Up, protein, iron, calcium, etc, which say they boost the Pokemon's [hp,atk,def,etc] stat each give that stat 10 EVs. However, these stop working if they have over 100 EVs in that stat, so you'll have to fight Pokemon from that point on. To speed up the process of gaining EVs from battle, you can use some items, like teh Macho brace. The Macho Brace lowers your speed in battle, but doubles all the EVs you get. This can make things go faster, but make sure you take it into account when totalling EVs.
As for how many you want, you can get up to 255. However, you only want 252 maximum. Since four EVs add one to the stat, 255 would increase the stat 63, and have three EVs left over. Three leftover EVs does nothing, so only train to 252 maximum and use the other three elsewhere. Some sites show the best EVs for Pokemon along with movesets that go well with those EVs. You might want to check those. Also, some is common knowledge. If you have a Pokemon with all physical attacks, boosting its attack stat would be good, but boosting its special attack would be pointless because it has no special moves. Most sites recommend training to 252 in two stats and using the 4 left over for another stat, though you can mix it up and try other combinations of stats.

It can take a while, but its worth it. If you're worried about waiting until level 100 for the full benefit, you still get a bunch on the way there, and also, if you do wi-fi battles, you can do a level 100 battle, where all Pokemon are set to level 100, and you'd gain all EV bonuses there.